{"title":"Geotechnical properties of the shallow type methane hydrate-bearing sediments in the Lake Baikal","authors":"S. Kataoka, S. Yamashita, H. Minami, S. Nishio, Abe Toru, T. Yokoyama, M. Hyodo, M. Grachev","doi":"10.3208/JGS.2.95","DOIUrl":"https://doi.org/10.3208/JGS.2.95","url":null,"abstract":"2005，2006年に，ロシア・バイカル湖にて実施した表層型メタンハイドレート賦存地盤調査から，湖底表層土の工学的特性について検討を行った。調査ではメタンハイドレートを含む湖底表層の堆積土採取，コア観察および現地船上試験（コーン貫入試験，ベーンせん断試験，ベンダーエレメント試験，一軸圧縮試験）を行った。その際，試料はメタンハイドレート含有堆積土のほかに，音波探査によりメタンハイドレートの存在が確認されなかった地盤からも採取し，各種試験での比較を行った。その結果，メタンハイドレートを含む地盤の表層堆積土は，メタンハイドレートが存在していない地盤の試料に比べて，測定値が堆積深度に依存せず，低い値を示した。この原因として，ガスや水の湧出による地盤の撹乱と試料採取時の応力解放が関係していると考えられた。","PeriodicalId":246019,"journal":{"name":"Jiban Kogaku Janaru (japanese Geotechnical Journal)","volume":"137 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116847810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Okuda, T. Tsuchida, Y. Watabe, K. Ueno, T. Kaneko, Hiroki Murakami
{"title":"Proposal of cutoff seawalls in coastal areas required high safety against the strong earthquake: - Experimental and numerical studies against the level 2 class strong earthquake -@@@－レベル２地震を想定した模型実験と数値解析－","authors":"K. Okuda, T. Tsuchida, Y. Watabe, K. Ueno, T. Kaneko, Hiroki Murakami","doi":"10.3208/JGS.10.343","DOIUrl":"https://doi.org/10.3208/JGS.10.343","url":null,"abstract":"","PeriodicalId":246019,"journal":{"name":"Jiban Kogaku Janaru (japanese Geotechnical Journal)","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131884614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Sanagawa, H. Nishioka, M. Koda, Tatsuya Morino, T. Yonezawa, Hihumi Aoki
At the soft ground, the earthquakes generate large ground deformations. The large ground deformations displace the pile foundations, and induce the large pile forces at deep location. But it is not clear about the behavior of damaged piles, therefore, piles are generally designed not to be damaged by kinematic and inertial forces. In consequence, piles at soft ground have large diameter and it is difficult to cut off of the longitudinal bars in case of reinforced concrete piles at shallow location. The aim of this paper is to propose the economic seismic design code of pile foundations, and we make a study on the effect of cutting off of longitudinal bars reinforced concrete pile on lateral resistance under kinematic and inertial interactions by model tests and numerical simulations. The results of model loading tests confirmed that the damage at stepped rebar arrangement by ground deformation had no effect on lateral resistance, if the piles are not damaged by inertial forces. And it was possible to simulate the experimentally results by the static nonlinear analysis procedure with seismic displacement method. As a result, it indicated possibility of design considering the damage by ground deformations. Abstract At the soft ground, the earthquakes generate large ground deformations. The large ground deformations displace the pile foundations, and induce the large pile forces at deep location. But it is not clear about the behavior of damaged piles, therefore, piles are generally designed not to be damaged by kinematic and inertial forces. In consequence, piles at soft ground have large diameter and it is difficult to cut off of the longitudinal bars in case of reinforced concrete piles at shallow location. The aim of this paper is to propose the economic seismic design code of pile foundations, and we make a study on the effect of cutting off of longitudinal bars reinforced concrete pile on lateral resistance under kinematic and inertial interactions by model tests and numerical simulations. The results of model loading tests confirmed that the damage at stepped rebar arrangement by ground deformation had no effect on lateral resistance, if the piles are not damaged by inertial forces. And it was possible to simulate the experimentally results by the static nonlinear analysis procedure with seismic displacement method. As a result, it indicated possibility of design considering the damage by ground deformations.
{"title":"Effect of cutting off of longitudinal bars of reinforced concrete pile on lateral resistance under kinematic and inertial interactions","authors":"T. Sanagawa, H. Nishioka, M. Koda, Tatsuya Morino, T. Yonezawa, Hihumi Aoki","doi":"10.3208/jgs.10.33","DOIUrl":"https://doi.org/10.3208/jgs.10.33","url":null,"abstract":"At the soft ground, the earthquakes generate large ground deformations. The large ground deformations displace the pile foundations, and induce the large pile forces at deep location. But it is not clear about the behavior of damaged piles, therefore, piles are generally designed not to be damaged by kinematic and inertial forces. In consequence, piles at soft ground have large diameter and it is difficult to cut off of the longitudinal bars in case of reinforced concrete piles at shallow location. The aim of this paper is to propose the economic seismic design code of pile foundations, and we make a study on the effect of cutting off of longitudinal bars reinforced concrete pile on lateral resistance under kinematic and inertial interactions by model tests and numerical simulations. The results of model loading tests confirmed that the damage at stepped rebar arrangement by ground deformation had no effect on lateral resistance, if the piles are not damaged by inertial forces. And it was possible to simulate the experimentally results by the static nonlinear analysis procedure with seismic displacement method. As a result, it indicated possibility of design considering the damage by ground deformations. Abstract At the soft ground, the earthquakes generate large ground deformations. The large ground deformations displace the pile foundations, and induce the large pile forces at deep location. But it is not clear about the behavior of damaged piles, therefore, piles are generally designed not to be damaged by kinematic and inertial forces. In consequence, piles at soft ground have large diameter and it is difficult to cut off of the longitudinal bars in case of reinforced concrete piles at shallow location. The aim of this paper is to propose the economic seismic design code of pile foundations, and we make a study on the effect of cutting off of longitudinal bars reinforced concrete pile on lateral resistance under kinematic and inertial interactions by model tests and numerical simulations. The results of model loading tests confirmed that the damage at stepped rebar arrangement by ground deformation had no effect on lateral resistance, if the piles are not damaged by inertial forces. And it was possible to simulate the experimentally results by the static nonlinear analysis procedure with seismic displacement method. As a result, it indicated possibility of design considering the damage by ground deformations.","PeriodicalId":246019,"journal":{"name":"Jiban Kogaku Janaru (japanese Geotechnical Journal)","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133387199","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"New approach for pumped water models and well loss euation for groundwater area control","authors":"H. Okuno, S. Koyama","doi":"10.3208/JGS.6.27","DOIUrl":"https://doi.org/10.3208/JGS.6.27","url":null,"abstract":"全国井戸台帳によると,深井戸は帯水層の地質構成に基づき，多層スクリーンを有する不完全貫入井戸が多い。この点は，水資源としての地下水の有効利用だけではなく，水環境の保全にとっても重大な問題である。したがって，一般に井戸設計では，施工コスト面を踏まえて，できる限り正確に計画揚水量を算定する必要がある。しかしながら，不完全貫入井戸の場合，水理定数の算定や揚水管理に関して井戸理論を正確に適用し難く，不適切な設計揚水量を導くこともあり，結果的に不正確な設計揚水量を算出することによって過剰揚水による井戸の枯渇の助長や地下水位の低下による地盤沈下の被害も多くなっている。本研究においては，安全な設計揚水量を導くために，プレボーリングによる帯水層の水理学的な地質特性，段階揚水試験及び定常説を用いて実用的な井戸損失式を提案して本式の有効性について考察した。すなわち，非定常説に基づくJacob法と対比される新しい揚水モデルによる井戸損失式を提案し，地下水盆を構成する地質が異なる地域や任意の井戸構造においても，同一の井戸損失式によって地下水管理が可能であることを実証的に明らかにした。","PeriodicalId":246019,"journal":{"name":"Jiban Kogaku Janaru (japanese Geotechnical Journal)","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133498022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hiroki Murakami, T. Tsuchida, Taiki Abe, Yuichi Tanaka, K. Ueno
{"title":"Study on mixture of marine clay with bentonite used for cutoff of coastal disposal facility for wastes containing radioactive cesium","authors":"Hiroki Murakami, T. Tsuchida, Taiki Abe, Yuichi Tanaka, K. Ueno","doi":"10.3208/JGS.10.17","DOIUrl":"https://doi.org/10.3208/JGS.10.17","url":null,"abstract":"","PeriodicalId":246019,"journal":{"name":"Jiban Kogaku Janaru (japanese Geotechnical Journal)","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133286149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Seismic behavior of reinforced soil wall combined with soil cement","authors":"J. Izawa, T. Saitoh, H. Itoh, M. Ueno, J. Kuwano","doi":"10.3208/jgs.2.73","DOIUrl":"https://doi.org/10.3208/jgs.2.73","url":null,"abstract":"筆者らは補強土壁の壁面部分に改良土を配置しジオグリッドと組み合わせる補強土工法の開発を進め，ここ数年で適用事例も伸ばしている。しかし，耐震性能に関しては未解明な部分が多く課題となっていた。そこで，本工法の耐震性能を把握することを目的として遠心模型振動実験を行った。その結果，従来のジオグリッドのみによる補強土擁壁や，改良土のみの擁壁と比較して高い耐震性を示すことが分かったが，最終的に改良土壁内にクラックが発生し破壊に至る可能性があることが分かった。このクラックは壁面パネルからのアンカーとジオグリッドを補強土壁内でオーバーラップさせることによって抑制できた。また，改良土に短繊維を混合することにより，引張り破壊後の残留強度の落ち込みを抑えることが出来，クラック発生を抑制できることが分かった。","PeriodicalId":246019,"journal":{"name":"Jiban Kogaku Janaru (japanese Geotechnical Journal)","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122348544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Effects of vertical load of superstructure on piled raft foundation in sand subjected to static horizontal and moment load","authors":"K. Sawada, J. Takemura","doi":"10.3208/JGS.11.85","DOIUrl":"https://doi.org/10.3208/JGS.11.85","url":null,"abstract":"","PeriodicalId":246019,"journal":{"name":"Jiban Kogaku Janaru (japanese Geotechnical Journal)","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123952898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Failure mechanism of cement treated clay with tire chips and change of its permeability under shear deformation","authors":"Y. Kikuchi, T. Nagatome, Y. Mitarai","doi":"10.3208/JGS.1.19","DOIUrl":"https://doi.org/10.3208/JGS.1.19","url":null,"abstract":"本研究では，マイクロフォーカスX線CTスキャナを用いて，ゴムチップ混合固化処理土供試体の密度分布や内部構造を観察した。また，ゴムチップ混合量の異なるいくつかの供試体について一軸圧縮試験の途中段階でX線CTスキャンや透水試験を行うことにより，せん断中の供試体内部の亀裂の進展状況と透水係数の変化について検討した。この結果，ゴムチップを混合することによって固化処理土の靭性が増し，透水係数の上昇が抑えられることを示した。","PeriodicalId":246019,"journal":{"name":"Jiban Kogaku Janaru (japanese Geotechnical Journal)","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121035533","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kyu Lee, T. Koyama, Y. Ohnishi, Hideaki Furukawa, Takaji Kobayashi
Recently, overflow due to the heavy rainfall causes the collapse of the river levee, as a result, serious flooding and damage. It is necessary to investigate the failure mechanism of the river levee due to the heavy rain and evaluate the stability of the river levee. According to the guideline for the design of the river levee, the seepage failure of the river levee is conventionally evaluated by the minimum safety factor of sliding, which is obtained from the circular arc calculation with the result of the seepage analysis. In this paper, the seepage failure caused by the overflow was mainly focused and simulated by newly developed coupled stress-water flow simulation code. In the numerical simulations, the seepage under saturated-unsaturated conditions considering rainfall, change of the water level, and overflow due to the heavy rain was solved and combined with the mechanical simulations. Stress and flow (seepage) were coupled only in the saturated zone and the coupled processes were not considered in the unsaturated zone. The simulation results clearly show the failure mechanism of the river levee by overflow.
{"title":"Coupled stress-flow simulations for the river levee considering overflow","authors":"Kyu Lee, T. Koyama, Y. Ohnishi, Hideaki Furukawa, Takaji Kobayashi","doi":"10.3208/JGS.4.1","DOIUrl":"https://doi.org/10.3208/JGS.4.1","url":null,"abstract":"Recently, overflow due to the heavy rainfall causes the collapse of the river levee, as a result, serious flooding and damage. It is necessary to investigate the failure mechanism of the river levee due to the heavy rain and evaluate the stability of the river levee. According to the guideline for the design of the river levee, the seepage failure of the river levee is conventionally evaluated by the minimum safety factor of sliding, which is obtained from the circular arc calculation with the result of the seepage analysis. In this paper, the seepage failure caused by the overflow was mainly focused and simulated by newly developed coupled stress-water flow simulation code. In the numerical simulations, the seepage under saturated-unsaturated conditions considering rainfall, change of the water level, and overflow due to the heavy rain was solved and combined with the mechanical simulations. Stress and flow (seepage) were coupled only in the saturated zone and the coupled processes were not considered in the unsaturated zone. The simulation results clearly show the failure mechanism of the river levee by overflow.","PeriodicalId":246019,"journal":{"name":"Jiban Kogaku Janaru (japanese Geotechnical Journal)","volume":"112 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129091267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Evaluation of the effect of inclination of reinforcement on horizontal bearing capacity of geo reinforcing type foundation","authors":"J. Izawa, H. Kusaka, N. Nakatani, M. Ueno, Hiroshi Sato, J. Kuwano","doi":"10.3208/JGS.3.55","DOIUrl":"https://doi.org/10.3208/JGS.3.55","url":null,"abstract":"地盤補強型基礎工法は，道路橋梁基礎および送電鉄塔基礎の支持力確保のためのコストダウン工法として開発され，実適用によりコスト縮減に効果を上げてきた。本研究は，近年増加している径5ｍ以上の大口径深礎に対応した工法への改良に向けた，合理的な補強形態の把握を目的としている。水平荷重を受けた大口径深礎は剛体的に回転すると考えられ，回転に対して有効に補強効果を得られる角度で補強材を打設する必要がある。そこで補強材打設角度に着目し，その影響について遠心場水平載荷試験にて検証を行った。実験から水平荷重を受ける地盤補強型基礎工法の補強メカニズムを明らかにした。また，打設角度45°で補強材に効率的に軸力が発生する補強形態となり補強効率は最適になった。この補強材に作用する軸力は，補強材に作用する周辺地盤からの拘束圧に対する打設角度の影響と，地盤の最小主ひずみ方向と補強材打設方向の差を考慮する補正係数f(θ)を評価することにより算出できた。これらの結果をもとに，梁バネモデルを用いた地盤補強型基礎の抵抗モーメント評価法を示した。","PeriodicalId":246019,"journal":{"name":"Jiban Kogaku Janaru (japanese Geotechnical Journal)","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129162730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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